import java.util.*;

class Calculator{
    private int num1;
    private int num2;

    public void setNum1(int num1){
        this.num1 = num1;
    }
    public int getNum1(){
        return num1;
    }
    public void setNum2(int num2){
        this.num2 = num2;
    }
    public int getNum2(){
        return num2;
    }
    public int add(){
        return this.num1 + this.num2;
    }

}


public class TestDemo {
    Calculator calculator = new Calculator();
    calculator.setNum1(10);
    calculator.setNum2(10);
    calculator.add();
}
